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A hint of the Greek word bios, meaning "life", can be seen in microbe. Microbes, or microorganisms, include bacteria, protozoa, fungi, algae, amoebas, and slime molds. Many people think of microbes as simply the causes of disease, but every human is actually the host to billions of microbes, and most of them are essential to our life. Much research is now going into possible microbial sources of future energy; algae looks particularly promising, as do certain newly discovered or created microbes that can produce cellulose, to be turned into ethanol and other biofuels.

Examples of microbe in a Sentence

Recent Examples on the Web
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Previous research has shown that microplastics can harm microbes in the ocean, for instance, and can change the behavior of fish. — Jackie Flynn Mogensen, Scientific American, 5 Nov. 2026 By fueling these microbes, fiber helps create a balanced gut microbiome (the community of microbes in the gut), which in turn supports regular digestion and reduces inflammation. — Lana Barhum, Verywell Health, 4 Nov. 2026 The new paper explicitly acknowledges that heme-producing microbes cannot be completely ruled out. — New Atlas, 2 Nov. 2026 Conversely, when those same seeds are planted outdoors, natural sunlight, open air, and competing soil microbes naturally neutralize the bacteria long before the plant reaches your dinner plate. — Sj McShane, Martha Stewart, 1 Nov. 2026 See All Example Sentences for microbe

Word History

Etymology

International Scientific Vocabulary micr- + Greek bios life — more at quick entry 1

First Known Use

1878, in the meaning defined above

Time Traveler
The first known use of microbe was in 1878

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Cite this Entry

“Microbe.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/microbe. Accessed 7 Nov. 2026.

Medical Definition

: microorganism, germ
—used especially of pathogenic bacteria
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